I am finally getting around to trying to tune my new engine. I am having a recurring problem that has pretty much always been happening with this car since I bought it. I need a little to insight as to what direction to head for troubleshooting.
Current combination is stock block 342, trick flow 190 fac heads, track heat intake, Comp XE276HR-12, 1.7 rockers, shorty headers, 39lb injectors, 80mm stock 96 mustang MAF, 70mm throttle body and 75mm elbow, aluminum flywheel.
Like I said, the car has done this off and on since I owned it, with different injectors and MAF meters. I had the injector harness apart to change the plugs to the EV6 style. While unwrapped I did inspect for damage and issues. I have pulled codes and only get the one for having a chip/tuner. O2 sensors have been replaced in the past as part of searching for the problem, and also just because they were so old. TPS shows smooth linear voltage, IAC has been swapped with a couple different Ford ones, distributor was replaced with a known good Ford unit, TFI module was also replaced with a known working Ford unit. I have also dressed up all grounds. I am starting to suspect a harness issue or ECM problem.
I dont have any logs, but it has on occasion, just died and was very very difficult to restart. It would pop and sputter and took alot of throttle work to get it going. Once running it would bellow out blackish smoke, pop, sputter, and finally clear up. Once cleared up, it was fine as long as it was moving. Then like magic, problem goes away for several days to weeks before reoccurring.
The car will idle fine at times with no issues. Other times, when coming to a stop, or after revving the engine, it will settle to a good idle, and just die. Basically like you turned the key off. I just started pulling datalogs to try to see whatss happening. The biggest thing I have noticed is my lambse1 and 2 go from 14ish to 10ish right before it dies and also the pw1 and 2 shoot up from low 1s to mid 10s when this happens. I am trying to learn this as I go, but work keeps getting in the way. I am attaching a data log that shows whats going on. I just out the cruising portions to help scale it down. I can also cut down on the things logged to help out.
Any and all help is greatly appreciated.